Hi, I see that Charli has built a greenhouse with an underground water heat sink and many other people are looking at the same idea.
I live in the South of England and have started a Victorian style lean-to greenhouse project in which I'm hoping to incorporate a heat sink to prevent winter freezing, grow a peach tree and extend the growing season.
The greenhouse would be circa 5m x 3m x3m at its highest point. The concrete foundations are in place for a double skinned rear and side wall which I may insulate. The side wall will be insulated with a compost heater and I wanted to utilise compost for inside heat too, not yet sure how.
A 1m x1m x 0.8m deep hole has been dug out for the heat sink. Clay and flint prevented us from going further as did the fact that I shouldn't have really undermined the foundations, so need to fill it back up asap. The intention was to use solid mass (pipes/fan/solar heater etc) but I'm now wondering if I should use water?
Does anyone have any experience of the efficacy of a water based heat sink system as opposed to solid mass, taking into account costs of set up? Any tips much appreciated.
